Answer:
The longest wavelength of light is 209 nm.
Step-by-step explanation:
Given that,
Spring constant = 74 N/m
Mass of electron

Speed of light

We need to calculate the frequency
Using formula of frequency

Where, k= spring constant
m = mass of the particle
Put the value into the formula


We need to calculate the longest wavelength that the electron can absorb

Where, c = speed of light
f = frequency
Put the value into the formula



Hence, The longest wavelength of light is 209 nm.